1. Field of the Invention
This invention relates to a photo printing apparatus having a data converter for converting inputted image data of photo film into print data with a print density level set for each pixel of images, and a print head for forming images on print sheets based on the print data.
2. Description of the Related Art
Such an image printing apparatus creates, from inputted image data of photo film, print data with a print density level set for each pixel of images, and forms images on print sheets based on the print data.
In setting the print data as above, the data converter performs a conversion process to convert the image data in a way to exclude color information intrinsic to the photo film which is included in the inputted image data. The data converter performs also an image quality correction process to correct the quality of the image data.
As is particularly conspicuous with negative film, photo film has color information (such as the base color of the photo film) corresponding to the type of photo film. This color information is included in the inputted image data of the photo film. To expose images photographed on the photo film properly, the color information intrinsic to the photo film must be excluded from the image data. The data converter carries out this process.
This basic conversion process is performed under different processing conditions to cope with different types of photo film. In principle, photo films are grouped according to type, or photo films having similar characteristics are grouped together, and processing conditions are set for each individual group. As distinct from this basic conversion process, the image quality correction process is, in a sense, a correction for the print head, and in conventional practice fixed processing conditions are set thereto.
With conventional photo printing apparatus, however, even where processing conditions are set for the basic conversion process by taking the type of film into account, the print image quality obtained is not always satisfactory. Thus, there is room for improvement.
The object of this invention is to eliminate the drawback of the prior art noted above and to achieve an improvement in the image quality of photo prints made from photo film.
In order to fulfill the above object, a photo printing apparatus according to this invention comprises a data converter for converting inputted image data of a photo film into print data with a print density set for each pixel in images, the data converter including a basic conversion processor for converting the image data to exclude color information intrinsic to the photo film from the inputted image data, and an image quality corrector for performing an image quality correction process for the image data based on attribute information on the photo film and with conditions corresponding to the photo film.
With this construction, the data converter converts inputted image data into print data for use in image formation by the print head, through a basic conversion process to convert the inputted image data to exclude color information intrinsic to the photo film from the inputted image data, and an image quality correction process for the image data based on attribute information on the photo film and with conditions corresponding to the photo film.
What is known as a digital photo printer that prints images based on print data with a print density set for each pixel in the images has, in recent years, been improved remarkably in print image quality also in a printing mode for exposing and forming images on printing paper, for example. However, although the data converter performs the basic conversion process to exclude color information intrinsic to photo film from inputted image data, variations do occur in print image quality with different types of photo film. The inventor herein has found that such variations are due to image quality correction processes carried out with uniform processing conditions.
As a specific example easy to understand, although images of a high sensitivity film with a coarse particle photosensitive material are to be printed, the data converter may carry out a sharpness correction by way of image quality correction process, with settings based on a low sensitivity film with a fine particle photosensitive material. In such a case, the resulting print quality could present a somewhat rough impression.
To avoid such an inconvenience, the data converter according to this invention performs an image quality correction process based on attribute information on a photo film and with processing conditions corresponding to the photo film. Such an elaborate image quality correction process enables a further improvement in print image quality.
The above attribute information on photo film may consist, for example, only of information on the sensitivity of the photo film, depending on the image quality correction process to be performed. In that case, only the sensitivity information may be inputted as attribute information. Conversely, where inputting of a particular characteristic of photo film is inadequate, the brand of photo film, for example, may be inputted as attribute information. Generally, such attribute information is recorded on the photo film itself or on a package or the like of the photo film. This recorded information may be read and inputted.
In a preferred embodiment of this invention, the photo printing apparatus further comprises an attribute information getter for acquiring the attribute information on the photo film. The attribute information on the photo film acquired by this attribute information getter is used in the image quality correction process performed by the image quality corrector.
Attribute information on photo film may be inputted by the operator. However, the operator""s workload may be lightened, for example, by automatically detecting attribute information on photo film recorded on the photo film itself or on a package or the like of the photo film.
In another preferred embodiment of this invention, the data converter includes a correction information storage storing processing information for execute the image quality correction process. This construction can promptly change the processing conditions in response to a change in the type of photo film handled. Further, the processing information stored in the correction information storage may be revisable in response to an image quality correction data change instruction inputted from a manually operable input device. Then, by rewriting the data in a look-up table by an input operation made by the operator, for example, a fine adjustment may be made to the processing conditions already set for the image quality correction process. This feature provides a flexibility for coping with a necessity for changing the processing conditions caused by various factors.
In a preferred embodiment, new processing information for the image quality correction process is storable in the correction information storage in response to an image quality correction data register instruction inputted from a manually operable input device. In this case, when starting to use a new type of photo film not having been used at all, processing conditions for this type of photo film may be registered in the look-up table, thereby to realize prints of excellent image quality.
In a preferred embodiment, the correction information storage includes a program file for storing various correction programs corresponding to the photo film attribute information, and a look-up table for storing various correction factor data corresponding to the photo film attribute information.
Other features and advantages of this invention will be apparent from the following description of the embodiment to be taken with reference to the drawings.